Case Study

Efficient Decolorization of Anodizing Wastewater

Using Bluwat Water Decoloring Agent + PAC + PAM

Project Background

A metal surface treatment plant specializing in aluminum anodizing was facing serious wastewater discharge challenges. The effluent contained:

• High color intensity

• Residual dye and metal complexes

• High turbidity

• Unstable COD levels

The wastewater appeared dark and visually unacceptable for discharge, even after traditional treatment.

The client required:

• Rapid color removal

• Stable clarification

• Reduced sludge volume

• Cost-effective chemical dosing

Bluwat Chemicals provided a laboratory jar test demonstration and optimized a three-step treatment solution.

Treatment Solution Overview

Bluwat recommended a combined chemical program:

1. Water Decoloring Agent (Step 1)

2. Polyaluminum Chloride PAC (Step 2)

3. Polyacrylamide PAM (Step 3)

This staged dosing strategy ensures maximum color removal and floc formation efficiency.

Step-by-Step Treatment Process

Step 1 – Addition of Water Decoloring Agent

Bluwat Water Decoloring Agent was first added to the anodizing wastewater.

Function:

• Strong cationic charge neutralization

• Breakdown of dye molecules

• Initial color removal

• Destabilization of colloidal particles

Result:
The deep-colored wastewater rapidly began to lose intensity, indicating effective molecular destabilization.

Step 2 – Addition of PAC

Polyaluminum Chloride was then introduced.

Function:

• Further coagulation

• Capture of destabilized particles

• Reduction of turbidity

• Improved sedimentation

Result:
Fine suspended solids began forming visible micro-flocs.

Step 3 – Addition of PAM

Finally, Polyacrylamide flocculant was dosed.

Function:

• Polymer bridging

• Formation of large dense flocs

• Rapid sedimentation

• Clear supernatant formation

Result:
Large compact flocs settled quickly, leaving clear and transparent water in the upper layer.

Final Treatment Result

After the three-step process:

• Significant color removal achieved

• Turbidity greatly reduced

• Fast solid-liquid separation

• Stable clarified effluent

The treated water met discharge standards and significantly improved visual quality.

Why This Combination Works for Anodizing Wastewater

Anodizing wastewater typically contains:

• Metal ions

• Organic dyes

• Complex chemical additives

Single-chemical treatment often fails due to complex molecular structures.

Bluwat’s staged approach ensures:

✔ Molecular-level dye destruction
✔ Charge neutralization
✔ Coagulation
✔ Polymer bridging
✔ Efficient sedimentation

Client Benefits

• Lower overall chemical consumption

• Faster sedimentation time

• Reduced sludge handling cost

• Improved compliance reliability

• Easy integration into existing systems

About Bluwat Chemicals

Bluwat Chemicals is a global manufacturer of water treatment chemicals with over 25 years of production experience. Our products are exported to more than 100 countries and widely used in:

• Textile wastewater treatment

• Metal surface treatment

• Paper mills

• Municipal plants

• Mining and oilfield applications

With in-house laboratory support and daily wastewater sample testing, we help customers optimize chemical selection before full-scale implementation.